Issue 39, 2019

Efficient occlusion of oil droplets within calcite crystals


It is well known that oil and water do not mix. Similarly, the incorporation of oil droplets within inorganic crystals is highly counter-intuitive because there is a large difference in surface energy for these two components. Nevertheless, herein we demonstrate the efficient occlusion of ∼250–500 nm oil droplets within 20–40 μm calcite crystals. These droplets are stabilized using various amphiphilic poly(methacrylic acid)–poly(n-alkyl methacrylate) diblock copolymer emulsifiers. Both copolymer concentration and diblock compositions affect the extent of occlusion, with optimized conditions producing calcite crystals containing up to 11% oil by mass. Moreover, compressive forces exerted by the growing crystals cause significant deformation of the oil droplets during occlusion. In principle, this protocol enables the incorporation of water-insoluble dyes or hydrophobic nanoparticles within calcite, which is a cheap, naturally-occurring and environmentally-benign mineral. The single crystal nature of this host lattice ensures efficient retention of such guests, while lowering the solution pH leads to triggered release via acid dissolution.

Graphical abstract: Efficient occlusion of oil droplets within calcite crystals

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Article information

Article type
Edge Article
08 Jul 2019
09 Aug 2019
First published
09 Aug 2019
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2019,10, 8964-8972

Efficient occlusion of oil droplets within calcite crystals

Y. Ning, F. C. Meldrum and S. P. Armes, Chem. Sci., 2019, 10, 8964 DOI: 10.1039/C9SC03372F

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